Metal material for electronic parts, electronic parts, electronic apparatuses, and method of processing metal materials
The present invention relates to a metal material for electronic parts, electronic parts, electronic apparatuses, and method of processing metal materials. For example, the present invention can be applied to liquid crystal display panels, various semiconductor devices, wiring boards, chip parts, and the like. The present invention uses metal material, more specifically an alloy comprising Ag as a main component, 0.1 to 3 wt % of Pd, and a total of 0.1 to 3 wt % of elements such as Al, Accordingly, the present invention provides a metal material for electronic parts, electronic parts and apparatuses using this metal material, whereby the metal material is characterized by lower resistivity, higher stability, and more excellent processability than the prior art.
Conventionally, wires, electrodes, and contacts of electronic parts and apparatuses use metal materials such as pure metals including Cu, Al, Mo, Ta, W, Cr, and the like, and alloys including Alxe2x80x94Cu, Alxe2x80x94Cuxe2x80x94Si, Alxe2x80x94Pd, TaSi, WSi, and the like for forming wiring patterns.
For example, a transparent liquid crystal display panel constituting a flat panel display generally uses pure Al as a wiring material because of excellent etching characteristics and low electrical resistance. However, pure Al shows a melting point of as low as 660xc2x0 C. Using pure Al as wiring material for liquid crystal display panels leaves the possibility of causing defects such as a hillock and a whisker during heat treatment at approximately 300xc2x0 C. to 400xc2x0 C. for a chemical vapor deposition (CVD) process after wiring film formation. Some types of liquid crystal display panels prevent these defects by using high-melting point materials for wiring such as Ta, Mo, Cr, W, and the like which are stable at a high temperature instead of pure Al.
A reflective liquid crystal display panel requires a high-reflectance layer which reflects transmitted light through liquid crystal cells. Such a high-reflectance layer or members for wiring patterns and electrodes functioning as a high-reflectance layer use pure Al, an Al-based alloy, pure Ag, an Ag-based alloy, Au, and the like. An electro-optical part (hereafter called an electro-optical part using micromirrors) uses micromirrors arranged on a silicon chip and displays images by means of optical modulation of each mirror. Such an electro-optical part uses pure Al for mirror members.
If there is provided a metal material which is characterized by lower electrical resistance, higher stability, and more excellent processability than metal materials used for conventional electronic apparatuses, using such a metal material for various electronic parts can improve performance and simplify manufacturing processes.
A transparent liquid crystal display panel uses Ta, Mo, Cr, W, and the like instead of pure Al in order to prevent defects. As shown in Table. 1, however, these materials have a disadvantage of larger resistivity than pure Al. If the transparent liquid crystal display panel becomes larger and provides higher resolution, the wire length for wiring patterns increases and wiring patterns become much finer, making it difficult to provide easy, reliable operations. For this reason, optimal wiring materials are unavailable for transparent liquid crystal display panels.
A reflective liquid crystal display panel and an electro-optical part using micromirrors allow wires and electrodes to serve as a high-reflectance layer. In this case, it is necessary to add requirements for a high-reflectance layer to wiring material characteristics for transparent liquid crystal display panels.
From the viewpoint of effectively reflecting incident light on the high-reflectance layer, pure Ag is an optimal material for high-reflectance layers because pure Ag provides the highest reflectance in a visible light wavelength region. However, pure Ag has weak corrosion resistance, not suitable for a wiring or electrode material. For this reason, optimal wiring materials are not always available also for reflective liquid crystal display panels and electro-optical parts using micromirrors.
In consideration of these points, the reflective liquid crystal display panel uses a barrier layer formed on, or on and below the high-reflectance film and the wiring electrode layer to improve corrosion resistance. However, increasing steps for forming barrier layers complicates the manufacturing process. Further, if the barrier layer is formed, its reliability remains unstable under high-temperature conditions.
As low-resistance wiring materials, Au, Cu, and Ag show lower resistivity than that of Al. However, Au is not easily available. Cu is characterized by poor corrosion resistance, provides degraded processability by etching, and presents difficult problems in fine processing. Ag excessively reacts on chloride, sulfur, and sulfide, offering problems in fine processing and corrosion resistance.
For example, Ag reacts excessively during a dry etching process by means of etching gas containing chlorine. As the etching process proceeds, Ag reacts on chlorine in the etching gas, generating AgCl on a boundary surface of the wiring pattern. This AgCl degrades electrical conductivity and thermal conductivity.
Here is an example in which Ag causes problems concerning corrosion resistance. When Ag is applied to a reflective liquid crystal display panel, there is a strong possibility of reacting on oxygen or a small amount of sulfur and the like on an interface by direct contact with a transparent conducting layer. Similarly to Al, it is necessary to form a barrier layer on the substrate layer or place the substrate layer between barrier layers in a sandwich structure.
In many cases, these liquid crystal display panels use a TFT (thin film transistor) comprising amorphous silicon or polycrystal silicon as a drive device. Presently, optimal electrode materials are unavailable from the viewpoint of drive devices.
Some of these drive devices simplify a manufacturing process by oxidizing metal material of electrodes and forming a gate insulating film between this electrode and a silicon active element. This is called an anodic oxidation method.
Of wiring materials shown in Table 1, Al and Ta can form gate insulating films. Especially, Ta can form an oxide insulating film which causes little defects such as pinholes and provides a high yield. However, Ta is characterized by high resistivity. When the anodic oxidation method is used, an electrode structure requires 2-layer wiring using Al with low resistivity, increasing manufacturing processes. When the 2-layer wiring is used, the resistivity of wiring patterns becomes same as that determined by Al.
In addition to application to the above-mentioned display devices, semiconductor devices such as DRAM, flash memory, CPU, MPU, and ASIC require a narrower wiring width due to high integration. The wiring length for wiring patterns is becoming longer due to increasing chip sizes and complicated wiring such as multilayer interconnection. These semiconductor devices also require wiring materials which are characterized by low resistivity, stable operations, and excellent processability.
Narrowing the wiring width and extending the wiring length increases the wiring resistance. Increasing the resistance also increases a voltage drop on wiring and decreases a drive voltage for elements. Further, the power consumption increases, causing a delay in signal transmission due to the wiring.
In addition to these semiconductor devices, electronic parts such as printed-wiring boards, chip capacitors, and relays use Cu and Ag for wiring, electrode, and contact materials. These materials also provide practically incomplete corrosion resistance and make the recycled use difficult.
The present invention has been made in consideration of the foregoing. The invention aims at proposing a metal material for electronic parts which is characterized by lower resistivity, more stable operations, and more excellent processability than existing materials. The invention also aims at proposing electronic parts, electronic apparatuses, electro-optical parts using this metal material, and a method of processing the metal material.
For solving these problems, applies to a metal material for electronic parts. The metal material comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of at least any one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to a metal material for electronic parts. The metal material comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % of an element selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to electronic parts made of a specific metal material, wherein wiring patterns, electrodes, or contacts are formed on these parts. The metal material comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to electronic apparatuses made of a specific metal material, wherein wiring patterns, electrodes, or contacts are formed on these parts. The metal material comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0. to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si. The invention applies to a processing method of metal materials. The processing method forms wiring patterns, electrodes, or contacts by using a solution containing phosphoric acid to etch a metal film comprising an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to a processing method of metal materials. The processing method forms wiring patterns, electrodes, or contacts by using a gas atmosphere containing chlorine to etch a metal film comprising an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to a device processing method including metal materials. When the metal material includes a metal film comprising an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si, the processing method processes materials other than the above-mentioned metal film by using etching in a gas atmosphere containing fluorine.
The invention applies to a processing method of metal materials. The processing method forms wiring patterns, electrodes, or contacts by heat-treating a metal film within a temperature range from 300xc2x0 C. to 750xc2x0 C. Thereby, the metal film comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si. The invention applies to a processing method of metal materials. The processing method forms wiring patterns, electrodes, or contacts on a substrate made of W, Ta, Mo, indium tin oxide, titanium nitride, silicon oxide, or silicon nitride, Si or amorphous Si. Thereby, wiring patterns, electrodes, or contacts comprise an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to a processing method of metal materials. The processing method forms wiring patterns, electrodes, or contacts by directly forming a metal film on a glass or plastic substrate. Thereby, the metal film comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
The invention applies to electro-optical parts made of a specific metal material, wherein reflection films, wiring patterns, electrodes, or contacts are formed on these parts. The metal material comprises an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si.
It is possible to improve weather resistance for the entire Ag by adding Pd to Ag and evenly mixing Pd into the grain boundary of Ag. Decreasing the resistivity is possible by adding one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si. This third element can suppress a rate of increase in the resistivity. Improving the weather resistance requires 0.1 to 3 wt % of elements to be added.
It is possible to produce an alloy by providing an AgPd alloy with 0.1 to 3 wt % of one or a plurality of elements selected from a group consisting of Al, Au, Pt, Cu, Ta, Cr, Ti, Ni, Co, and Si. Such an alloy maintains excellent thermal conductivity of pure Ag. This alloy can conform to conventional film formation processes such as the sputtering method, the vaporization method, the CVD method, and the plating method. The alloy can easily provide patterning by means of the wet etching technique and the dry etching technique. The alloy can maintain stable states at a high temperature.
It is possible to provide a metal material for electronic parts which is characterized by lower resistivity, more stable operations, and more excellent processability than existing materials.
It is possible to provide electronic parts whose wiring patterns, electrodes, or contacts use a metal material for electronic parts, wherein the material is characterized by low resistivity, stable operations, and excellent processability.
It is possible to provide electronic apparatuses whose wiring patterns, electrodes, or contacts use a metal material for electronic parts, wherein the material is characterized by low resistivity, stable operations, and excellent processability.
Such a ternary alloy permits etching using a phosphoric-acid-based etching solution such as H3PO4+HNO3+CH3COOH. It is possible to control an etching rate by adding water, cerium nitrate, and silver nitrate as well as phosphoric acid, nitric acid, and acetic acid.
It is possible to provide a patterning technique appropriate to this type of metal materials in addition to conventional patterning techniques.
Such a ternary alloy permits dry etching in a gas atmosphere containing chlorine. For example, RIE (reactive ion etching) and plasma etching are available in a gas atmosphere containing chlorine such as Cl2, CCl4, BCl3, and SiCl4.
It is possible to provide a patterning technique appropriate to this type of metal materials in addition to conventional patterning techniques.
This ternary alloy makes it difficult to perform dry etching in a gas atmosphere containing fluorine, providing an advantage that the alloy is free from a damage due to these gases. It is possible to prevent the ternary alloy from being etched by means of RIE or plasma etching in a gas atmosphere containing fluorine such as CF4, C3F8, C4F8, and SF6. However, it is also possible to etch other mate such as Si, polycrystal Si, amorphous Si, SiO2, Si3N4, Mo, W, Ta, Ti, and Pt.
The present invention can be applied to devices comprising this type of metal materials and the other materials and provide an optimal patterning technique.
The present invention can be applied to a processing method of metal materials. It is possible to form, say, deposition layers composed of this alloy using vaporization, CVD, or the like, and then alloy them. The alloy excels in stability at a high temperature. It is possible to maintain a stable state during high-temperature processes after film formation using various film formation methods. The alloy can be applied to various devices requiring high-temperature processes, thus providing wiring patterns and the like which are stable and excel in processability.
The present invention can be applied to a processing method of metal materials. Wiring patterns, electrodes, or contacts made of this type of alloy are formed on a substrate comprising any one of W, Ta, Mo, indium tin oxide, titanium nitride, silicon oxide, and silicon nitride. Conventional processing processes are applied to ensure sufficient adhesion properties. There are provided wiring patterns and the like which are characterized by low resistivity, stable operations, and excellent processability.
The present invention can be applied to a processing method of metal materials. Wiring patterns, electrodes, or contacts made of this type of alloy can be directly formed on a glass or plastic board. In this case, Al suppresses an increase in the resistivity because such an alloy is subject to little effects of oxygen. Accordingly, an easy manufacturing process can be employed to effectively fabricate wiring patterns with low resistivity.
The present invention can provide electro-optical parts whose reflection films, wiring patterns, or electrodes are made of a metal material which is characterized by low resistivity, stable operations, and excellent processability and reflectance.
As mentioned above, a metal material according to the present invention can be an alloy of Ag as a main component, 0.1 to 3 wt % of Pd, and 0.1 to 3 wt % in total of elements such as Al. There can be provided a metal material for electronic parts, electronic parts and apparatuses using this metal material, whereby the metal material is characterized by lower resistivity, higher stability, and more excellent processability than the prior art.